1. Field of the Invention
The present invention concerns an injection system for medical imaging examinations with a manually operated injector.
2. Description of the Prior Art
In medical imaging examinations, contrast agents dissolved in liquid often are administered. These injections, which are known as bolus injections, enable a more marked contrast in the imaging of tissues with the examination device. Given a temporally well-defined bolus injection as well as improvement of the contrast, details can be derived from the temporal progression with which the contrast agent spreads out in the tissue, for example, about disturbances in the blood-tissue barriers,. The temporal coordination, i.e. the timing of the bolus injection and the start of the measurements with the radiological examination device, is fundamental for reproducibility and high quality in this technology. In the majority of cases, the bolus injection is done manually with a syringe by the doctor. The point in time of the injection is then communicated by a verbal notification to the operator of the radiological examination device. In addition, automated injectors are known which are controlled via a terminal. These have the disadvantage that complications may become apparent too slowly, since the automatic bolus injections generally are not directly monitored. Complications that can occur during an injection are, for example, a leak or tear in the injection tube.
A device for contrast density regulation is known from German OS 19 647 701. The device comprises a sensor that is connected to a processing unit. The sensor can determine the concentration of contrast agent or the contrast density in individual areas of the body. A comparison of measured and rated values is converted into a control pulse that is transmitted to a pump system.
German PS 3 419 347 shows a device to continually output a disinfected, sterile, physiological liquid that, given increasing depletion, exerts a consistent pressure on the liquid.
An injection device for x-ray contrast agent is described in German OS 1 566 585 that has a constant injection output that is independent of geometry, viscosity, and flow resistance of the injected substance.
A device for determining the concentration of at least one substance present in an organic tissue with a pump-and-suction device controlled by a microprocessor is disclosed in German OS 4 123 441.